1. Field of the Invention
The present invention pertains to the beneficial treatment of liquids, such as water for food processing and other uses, and in particular to such treatments carried out in multiple stages.
2. Description of the Related Art
Many commercial and resiential water supplies suffer from "hard water" and other objectionable conditions. Oftentimes, remedial measures are implemented with the addition of chemical treatments to the water supply. In order to provide effective treatment and to prevent other problems from occurring, it may be necessary to carefully meter the amount of chemical treatment agent to a given quantity of supplied water.
A liquid treatment apparatus as described in commonly assigned U.S. Pat. No. 5,507,945 has proven commercially successful, particularly in the treatment of water supplies used for food preparation and other applications. The liquid treatment apparatus provides a chemical treatment agent which is put into solution and mixed with water flowing through the apparatus. More particularly, the liquid treatment apparatus includes a dispense head which develops a venturi action which is applied so as to help meter relatively small amounts of treatment chemical in the fluid flow. The liquid treatment apparatus includes, in addition to the aforementioned dispense head, a canister which threadingly engages the dispense head and which receives a container holding the chemical agent. The dispense head is typically joined to a piping system and has means for attachment to a mounting bracket if additional support is required. In operation, the canister is unthreaded from the dispensing head to allow replenishment of the chemical treating agent, as may be required. While the chemical treatment apparatus has been met with widespread commercial acceptance, it is desirable to provide low cost alternative systems which can be made operational by a simple retrofit to existing equipment, such as pre-filter housings, which are easily implemented by operators who are not familiar with dispenser and fluid metering technologies.
U.S. Pat. No. 5,580,448 discloses a chemical dispenser having a cartridge, used either alone or with an outer surrounding filter sleeve. The cartridge includes an apertured mid-section located between an upper solid wall conduit segment and a lower chemical-containing cartridge member which includes a dispensing aperture at its upper end. Thus, the amount of chemical treatment agent which can be provided, is reduced by the amount of the combined volume of the solid wall conduit segment and the apertured mid-section.
In various types of commercial activities, such as produce handling, food stores and restaurants, the available domestic water supply is employed to carry out commercial operations. Remedial measures to address problems of corrosion and scaling, are sometimes carried out with the introduction of small amounts of a treatment chemical, such as polyphosphate or sodium silicate, into the domestic water supply. Operators of the commercial establishments may not have the time or training required to appreciate the subtle operations of the chemical dispensing systems which are relied upon to control various water supply problems. It is advantageous to provide water treatment apparatus which is readily understood and easily maintained by operators of commercial establishments and other members of the community requiring water treatment.